Environmental Modelling & Software 18 (2003) 915–927 www.elsevier.com/locate/envsoft Reasoning with direction and rate of change in vegetation state transition modelling Brian S. McIntosh a,* , Robert I. Muetzelfeldt b , Colin J. Legg b , Stefano Mazzoleni c , Pe ´ter Csontos d a School of Water Sciences, Cranfield University, College Road, Cranfield, Bedfordshire MK43 0AL, UK b School of Earth, Environmental and Geographical Sciences, The University of Edinburgh, Darwin Building, King’s Buildings, Edinburgh EH9 3JU, UK c Dipartimento di Arboricultura, Botanica e Patologia Vegetale, Universita ` di Napoli “Federico II”, Facolta ` di Agraria, 80055 Portici (NA), Italy d Department of Plant Taxomony and Ecology, Lora ´nd Eo ¨tvo ¨s University, Pa ´zma ´ny P. se ´ta ´ny 1/c, Budapest H-1117, Hungary Received 28 August 2002; received in revised form 24 December 2002; accepted 12 March 2003 Abstract Better integration in land planning and management can be supported through the use of suitable model-based tools. Vegetation state transition models have been noted as being useful in this context, providing a simple, useful means of capturing available ecological knowledge. We describe a simple ‘proof of concept’ rule-based system developed to contribute methodologically to management-oriented modelling of vegetated landscapes. The system is based upon a clear separation of direction from rate of change and the use of a general temporal reasoning system, a feature that facilitates modelling of situations where environmental change occurs causing an increase or decrease in rate without affecting direction of vegetation change. To ease model development and use the system represents vegetation dynamics in a way that has a close correspondence to the structure of understanding communicated by vegetation ecologists. A test model is described and run under different conditions to demonstrate the system. The results show that although the rule-based system and in particular the temporal reasoning system used operate successfully, there are a number of deficiencies in the modelling system as currently implemented. Future development possibilities are detailed along with a broader discussion regarding the needs of management-oriented modelling and the utility of state transition approaches.  2003 Elsevier Ltd. All rights reserved. Keywords: State transition modelling; Rule-based modelling; Vegetation dynamics; Management-oriented modelling; Modelling systems; Mediter- ranean vegetation 1. Introduction—management-oriented modelling Given current political pressures for greater inte- gration in regional land planning (e.g. the River Basin Management Plans mandatory under the EU’s recent Water Framework Directive—see Chave, 2001), there is an identified role for model-based tools to provide infor- mation support. It has been recognised that land-use and land-cover both affect landscape dynamics and require joint treatment (Turner II et al., 1995)—an understand- * Corresponding author. Tel.: +44-1234-750111; fax: +44-1234- 751671. E-mail address: b.mcintosh@cranfield.ac.uk (B.S. McIntosh). 1364-8152/$ - see front matter  2003 Elsevier Ltd. All rights reserved. doi:10.1016/S1364-8152(03)00055-0 ing of the cover dynamics of vegetated land-use types under different management and natural conditions is therefore required. In this context suitable methods for simulating vegetation dynamics could be of use in for- mulating management plans. However, if such methods are to be of practical use they will require appropriate problem-, user- and organisation-centred designs (see Oxley et al., 2002). Tool designs must adequately cap- ture the relevant characteristics of relevant environmental/ecological processes, satisfy the needs of managers without providing too much information (volume and precision) and not require prohibitively expensive data collection for parameterisation/ initialisation. We take the view that the provision of modelling sys-